Hi all, 

So we have an Octavia mk2 cr170 

 

Car won't start unless the fuel metering valve on hpp is unplugged.  And even then it barely starts 

 

Once started can plug back in the valve and after about 20 seconds of hunting for idle and keeping the car alive it will steady out and idle somewhat okay! 

 

Fuel pressure seems to be fluctuating badly. Can't keep up with requested pressure most the time will sit within 50bar of required 

Only fault code I've had from the car is P0087 fuel pressure low 

 

I really can't get to the bottom of it. And I can't tell you what's been done to the car before to try..  but here's what I've tried.

 

-Checked pump for swarf! Nothing totally clean and seems to be working as should 

-Changed injectors for spairs we had lying arround, codded in. No change 

-changed fuel rail with pressure sensor and pressure regulator. No change

-changed fuel metering valve on pump 

-checked flow into high p pump. Decent flow  

-back proped metering valve and regulator and they are both getting a good pwm signal from ECU, will hold their duty cycle steady no fluctuation there 

- changed fuel filter 

- tried a different head from another high pressure pump. Just to check if the head was playing up. No change (rest of the pump looks okay and seems to be operating as should! 

- tried to readapt the regulator. I'm not sure if this was successful. 

 

Really only mechanical things left to change is the whole high pressure pump and both the elecy pumps, fuel lines and tank itself. 

 

I don't have vcds but do have a snap on diagnostic machine with a scope. 

 

It seems like the fault is due to pressure regulator not keeping up. But I've tried a different one and still no luck. All of these changes and no improvement what so ever! 

in tank pump.

Any luck with this? I have similar issues.

1 minute ago, stu987 said:

Any luck with this? I have similar issues.

Not yet, I'm getting a new ECU for it tomorrow so I will let you know.  After having many vag specialist look at it and not finding any hardcore faults decided to send the ECU of.   Will know tomorrow 🤞

2 minutes ago, stu987 said:

Any luck with this? I have similar issues.

So we have changed. Basically full fuel system other than lines and tank itself.  Have checked all wiring and solenoids etc..  have scoped relevant parts and getting correct Pwm on all..  only thing we have noticed is it's possibly the ECU that's not reading the fuel pressure and that's a fault within itself.   But soon will see

👍 ye drop us a message would be interesting to know. cheers 

On 17/01/2024 at 19:59, stu987 said:

👍 ye drop us a message would be interesting to know. cheers 

Hi mate, ECU didn't fix fault.  Didn't really think it would since the Pwm to all valves seem to be correct. But was worth a shot.. since I can send it back anyway.    Now I have put a used pump on it and nothing changed still seeing 0bar of fuel pressure.  So I'm going to invest in a high pressure test kit.. this will allow me to blank of the metering valve on pump and test the output of the pump itself etc..  will give me a good answer of where to look next.  

Can i just check youve reviewed the intank pump and lpfp controller?